We are studying neural mechanisms that relate to and account for auditory sensation and behavior. Our basic interest is in how the auditory system is organized to measure and encode cues relevant to certain acoustic phenomena, especially sound localization and pitch. Organizational principles can be revealed through experiments which relate the response of single neurons (recorded with use of microelectrodes) to binaural acoustic stimuli to their location within auditory nuclei. These binaural stimuli are known to be localized to certain positions in sensational space. The products of such experiments are functional maps that reveal how the spatial organization of the nuclei under study can account for their known functional (behavioral) results. That is, they show how neurons responsive to these binaural stimuli are arrayed within auditory nuclei; and they allow for the production of response-profile maps that reveal the total response within a nucleus arising from given binaular stimuli. It is an objective of these studies to produce such maps for the central nucleus of the inferior colliculus and primary auditory cortex in the cat. Organizational principles can also be revealed in anatomical-physiological studies of the projection from level to level in the system. These studies shall reveal how the response properties of neurons at the cortical level arise as a product of a complicated, highly-ordered projection system. These results shall be related to known psychoacoustic behavior, especially sound localization, and should provide basic information about how the auditory system is organized to generate these sensational phenomena.